X-ray image converter, device and method for recording, processing and illustrating images using X-rays and other rays

ABSTRACT

An X-ray image converter ( 2 ) for recording and evaluating information gained from X-ray investigations of persons ( 3 ), animals or objects and other purposes is suggested, which comprises a carrier ( 4 ) of a material in which the impinging X-ray radiation causes detectable changes, as well as a method for recording X-ray images, wherein changes in charge carriers on the surface of a carrier ( 4 ) are determined for evaluation of the radiation from the object ( 3 ) being observed.

[0001] This application is related to DE 198 50 608 filed Nov. 3, 1998the entire disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] The invention is based on a device and a method for recording,processing and illustrating X-ray images in accordance with thepre-characterizing part of claims 1 and 2.

[0003] Medicine uses X-rays for diagnosis. In technology, X-rays areused for testing, e.g. for testing material. Towards this end, theobject to be examined is subjected to X-ray radiation. The rays passingthrough the object are recorded by an X-ray image converter. Known X-rayimage converters are e.g. X-ray films which directly show the contrastednegative projected image. Moreover, polyester sheets coated with bariumhalogenide crystals are known which are scanned by a laser beam afterexposure to X-ray radiation and thereby emit light pulses of anintensity which corresponds to the intensity of the X-rays. The lightpulses are evaluated after digital image processing in a computer andcan be printed out. A further possibility of visualization of the X-rayimage is the use of fluorescence of different substances in the X-raylight. X-rays are also used in science and research for a wide range ofapplications.

[0004] Disadvantageously, known X-ray image converters require aconsiderably high radiation dose for satisfactory evaluation andvisualization. This is particularly disadvantageous since recordingsmust often be repeated. If e.g. CCD cameras or other detector systemsare used for recording the light pulses emitted by a crystal coating,the known methods have the further disadvantage that such systems may bedamaged with time by the X-ray radiation.

SUMMARY OF THE INVENTION

[0005] In contrast thereto, the inventive X-ray image converter havingthe characterizing features of the claims, has the advantage that acarrier is used for recordings which is an inexpensive, disposablecomponent which can be replaced after repeated use and whose surface,e.g. the charge carriers, is detectably changed by the impinging X-rayradiation. Evaluation is carried out not optically via a lens or viasecondary light emissions on a screen, but electrically. The inventivesystem has the further advantage that it is considerably more sensitivethan the known methods and image converters and therefore requires aconsiderably smaller radiation dose. The increased sensitivity is alsovery advantageous in other applications such as analysis, measuring,control and observation devices.

[0006] In accordance with an advantageous design of the inventive X-rayimage converter for electrostatic methods according to claims 2, 7, 8,9, the carrier consists of an insulating, electrically well chargeablematerial, in particular of plastic sheet. This material may contain airor gas in small cavities. This material has the advantage that even lowradiation energy deposition already causes changes in the chargecarriers which, however, do not discharge immediately. Scanning of thechange of the charge carriers is thereby possible within a certain timeafter exposure to the X-ray radiation.

[0007] In accordance with a further advantageous embodiment of theinvention, one side of the carrier is provided with an electricallyconducting coating. This causes uniform electric charging of that sideand also direct contact with the carrier, which is an insulator andwhich only becomes weakly conducting during irradiation. This coatingpermits an increase in sensitivity and uniformity.

[0008] In accordance with a further advantageous embodiment of theinvention, the other side of the carrier is provided with a plurality ofelectrically conducting surfaces which are electrically insulated fromone another. They are also electrically insulated from the conductinglayer described in the above paragraph. The plurality of surfaces form,together with the opposite surface, a plurality of separate capacitorshaving a certain capacitance. These surfaces are so-called pixels whichare ideally square and uniform but may also have other shapes. The size,number and distribution of these surfaces depend on the requiredresolution and also on other parameters such as sensitivity, noise andscanning methods.

[0009] Immediately before recording with e.g. X-rays, the two sides arecharged (polarized) with a constant D.C. voltage applied across the twosides. If the surface is fully covered, one single contact issufficient. In the case of one side having pixels, all surfaces must becontacted. This may be effected e.g. by a roller or in an analogousfashion. The detecting device or scanning device can also be configuredto perform this task. The charging contacts are then removed andirradiation follows to effect charge exchange and thereby a voltage dropat the individual capacitors or pixels. The voltage drop at eachindividual pixel is a function of the radiation intensity at this pixelor in the carrier layer (dielectric) of this pixel. After irradiation,the pixels are scanned as quickly as possible which may occur throughcontact or without contact (capacitively, through electrostaticinduction) or in a different conventional manner.

[0010] To increase the capacitance on the pixel surfaces, several layersof conducting laminates can be used, which are connected as required. Inthe basic version, the layers are parallel to the carrier. However, toincrease the capacitance, facilitate production, or for other reasons,the conducting layers must not necessarily be parallel to the carrier.

[0011] The principle of operation in the above embodiment can bemodified while still maintaining an operable device. The conductingsurfaces increase the scanning capability and the signal-to-noise ratio.In accordance with further advantageous embodiments of the invention,solutions other than conducting surfaces are possible. Omission of thepixel layer may produce a better resolution. There is, however, theassociated risk of systematic errors and increased noise. Moreover,other conventional physical methods which react to irradiation may beutilized optionally, and if advantageous, combined with the embodimentdescribed above.

[0012] The carrier is basically passive. In accordance with anadvantageous embodiment, electric conductors and current circuits, andfurthermore passive and/or active elements may be used on or in thecarrier, e.g. to generate or prolong maintenance of the polarizationvoltage, to intensify signals or to improve transmission to the detectordevice. Such devices can be powered and the information read-out viacontacts, inductively, capacitively or in a different conventionalfashion.

[0013] In an advantageous embodiment of the invention, the measurementof the electric voltage at the individual pixels may occursimultaneously with irradiation. In this case, the current to or fromthe pixels or the resistance may be measured, since each of thesequantities depends on the intensity of the rays at the respective pixel.The information content can be read out from the carrier during orfollowing irradiation. In this case as well, the pixels must be chargedbefore or during irradiation.

[0014] To extend the time between charging, irradiation and scanning, orfor other reasons, one or more masks can be used, having specificgeometric and electric properties with respect to the carrier, whichinfluence the pixel surfaces just before irradiation, using contacts orin a different fashion. An analogous or the same method may be carriedout between irradiation and scanning. Even during irradiation, the useof a mask may be advantageous. The mask is preferably disposed parallelto the carrier and can possibly contact or nearly contact the carrier.In another embodiment, the mask may be a roller which rolls over thecarrier or vice versa. In a further embodiment, the mask completely orpartially follows the movements of the carrier on the surface to beirradiated for imaging. The mask may also be on the side facing the raysas long as radiation attenuation is negligible or can be compensatedfor. In that case, it could be combined with the shadow casting deviceof claim 18.

[0015] The carrier may consist of more than one layer (sheet) or severalcarriers can be used at the same time. The different layers or carrierscan have specialized functions, can supplement one another, and cancooperate. They can move together, partially together, or differently.

[0016] The invention may also be used with radiation other than X-rays,depending on the purpose and type of carrier, e.g. with alpha, beta andgamma radiation. Detection of other particles and their tracks or ofcosmic radiation is also possible in this fashion.

[0017] In accordance with an advantageous embodiment of the invention,magnetic fields or magnetic field changes can be recorded which can alsobe processed and represented as two- or three-dimensional images. Thecarrier is equipped with appropriate conventional devices such aselectric circuits and/or materials having magnetic properties and thedetector device is correspondingly adjusted. To increase the sensitivityand accuracy, the carrier, its materials or parts thereof may bepre-magnetized or saturated before and/or during recording.

[0018] In accordance with a further advantageous embodiment of theinvention, a detector device is provided which can be moved relative tothe carrier for detecting the information contained on the carrier. Themovement between the detector device and the carrier is parallel to thecarrier surface, in one or two directions. After the action of theincident radiation, the carrier is scanned by the detector device. Sincethe carrier material is insulating, scanning can occur within a certaintime following action of the X-rays. The detector device can therebyeasily be protected from the radiation and is therefore not damaged.

[0019] In accordance with a further advantageous embodiment of theinvention, the detector device can be moved over the carrier in twodirections. The carrier itself is thereby stationary. The detector ofthe detector device may be punctiform. If several detectors are disposednext to one another to produce a detector device with one-dimensionalextent, it is sufficient to move same in one direction relative to thecarrier.

[0020] In accordance with a further advantageous embodiment of theinvention, the carrier, e.g. the plastic sheet, is disposed on rollersor cylinders to permit movement of the carrier relative to the detectordevice.

[0021] In accordance with a further advantageous embodiment of theinvention, the detection device within the detector is a field effecttransistor or an integrated amplifier provided with a field effecttransistor at the input thereof.

[0022] In accordance with a further advantageous embodiment of theinvention, a field effect transistor is used as the detection device inthe detector, however, without a gate: the electric field of the carriersurface thereby directly influences the current between the source anddrain, instead of the controlling gate electrode. This influence isrecorded and evaluated. Scanning of the carrier surface may be effectedwithout contact. This principle is provided in claim 20 as anembodiment. Therein, it is possible that many measuring pointssimultaneously act over a complete line width, similar to fax devices orpaper sheet scanners.

[0023] In accordance with a further advantageous embodiment of theinvention, several carriers are disposed in different spatial positionsrelative to the object to be recorded for recording spatially resolvedinformation. In this case, at least 2 X-ray radiation sources should beprovided or the position of the source should be changed relative to theobject.

[0024] In accordance with a further advantageous embodiment of theinvention, the information recorded by the detector device is evaluatedand displayed by means of a computer. The X-ray images may be stored inthe computer, printed out by printers and processed in a differentfashion.

[0025] In claim 3, scanning is effected, e.g. immediately in front ofthe rollers.

[0026] In claim 4, the solution depends on the physical principles ofthe carrier. The scanning roller may e.g. have contact points whichcontact the pixels individually to scan the information, or conductingsurfaces, optionally below a thin insulator, which scan the pixelswithout electric contact, e.g. capacitively. If deflecting rollerssimultaneously carry out scanning, the pixels are usually on the sidefacing the scanning rollers.

[0027] In claim 5 it is sufficient to move the detector device in onlyone direction, e.g. across the longer side of a rectangle, if itsdetectors are distributed over the entire width, i.e. across the shorterside of the rectangle, similar to a flat bed scanner for paper sheets.The detector device must have a number of detector points required forthe resolution.

[0028] In accordance with claim 6, the two or more information planespermit calculation of e.g. improved image resolution andthree-dimensional information, since i.a. the positions of radiationsources, objects and carrier levels are known. The planes are parallelto one another only in their simplest embodiment and may also havedifferent orientations.

[0029] Intermediate layers can be used in claims 7 and 8 to increase theeffect, e.g. to increase the capacity or sensitivity.

[0030] Claim 9 is directed towards a solution which increasessensitivity. To achieve the purpose of the invention, any conventionalmethod can be applied and optionally combined. The same is true forclaim 10.

[0031] Claim 11 differs from claim 6 in that the recording planes aredisposed not one behind the other but next to one another, with respectto the path of the rays.

[0032] Claim 12 cooperates geometrically with claims 11 and 6. Thedirection of radiation through the object is different, e.g. alsoperpendicular or at an angle with respect to one another.

[0033] In claim 16, the image converter does not record the radiationoriginating directly from the radiation source, influenced by theabsorption effects of the objects being examined, but rather radiationsources within the object itself which become sources followingirradiation by the actual primary radiation source. This point ispartially related to applications using optical microscopes with whichthe object is not observed using transmitted light but rather e.g. inthe dark field. In this case, the image converters are usually not inthe path of the rays of the radiation source, as in classical X-rayrecordings, but lateral or transverse thereto and are shielded from theprimary radiation. It is possible to simultaneously use severalconverters in accordance with the invention, even with only one primaryradiation source. The optimum angle or orientation depends on thephysical mechanism utilized. Deflection angles and other parameterswhich are further processed later for evaluation and representation canbe calculated numerically in a computer using the inventive converterand must not necessarily be searched for through mechanical adjustments,if the converters are sufficiently large. A special case of thisembodiment involves sources in an object which are not secondary butactually primary, i.e. real sources, in particular radioactive sources,such as radioactively marked capsules, agents, medication, tools,instruments, and also sources in space or on the earth. When the effectsand the inventive converter are reasonably combined, e.g. throughapplication of fluorescence effects, use of selective filters andspatial image recording, then through orientation of X-ray source andconverter in a same direction, even in close proximity to one another orinstalled in the same housing, e.g. mines, explosives or other objectscan be detected at large distances. With substances comprisingphosphorescence effects, the primary source is switched on forillumination, is then switched off and the recording is startedimmediately thereafter.

[0034] To improve contrast, selectivity and sensitivity, referencerecordings are taken without the object, and with object but withoutsearched features to be imaged (e.g. source of an illness, instruments,foreign bodies), and the features to be searched and their physicalproperties are recorded separately and are taken into considerationnumerically during evaluation and image representation.

[0035] Claim 17 describes an auxiliary means which casts defined shadows(in the relevant spectral range of the recording) onto the converter. Ina simple embodiment, identical round short rods of a suitable material,e.g. aluminum, are used, which are perpendicular to the converter. Therods have a similar effect as a sun-dial. The angle of impingement canbe determined numerically or in a different fashion and be displayed. Inan embodiment, the auxiliary means can be easily aligned towards thesource because the shadows thereby become minimal in size, reflectingmaximum absorption. In a similar manner, alignment towards secondarysources in accordance with claim 16 is also possible. One or severalprimary or secondary sources can be represented as an image or in adifferent manner following numerical processing. In principle, one rodis sufficient, however, a grid, mesh or another formation can also beused instead of rods. The length of e.g. the rods or the distance fromthe recording plane is given i.a. by the required angular resolution andthe resolution of the converter.

[0036] Claim 21 utilizes the same effect as in electret capacitormicrophones. The plastic material of the membrane is polarized duringproduction to always permit subsequent build-up of an electric voltage.The method known from microphone technology can be modified for theinventive application in the carrier, to facilitate or omit chargingbefore irradiation. Claim 21 can also be combined e.g. with claim 9 toimprove the results.

[0037] Further advantages and advantageous embodiments of the inventioncan be extracted from the following description, the drawing and theclaims.

[0038] The drawing shows an embodiment of the invention which isdescribed in more detail below.

BRIEF DESCRIPTION OF THE DRAWING

[0039]FIG. 1 shows a schematic representation of an arrangement of anX-ray source, a person to be examined and an X-ray image converter; and

[0040]FIG. 2 shows an embodiment of the X-ray image converter inaccordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0041]FIG. 1 shows an arrangement of X-ray source 1 and X-ray imageconverter 2 for recording X-ray images of a person 3. The X-rayconverter comprises a plastic sheet 4 carrier which is disposed on tworollers 5 which can support and transport the sheet. The plastic sheet 4can have a thickness of fractions of to tens of centimeters. Afterimpingement of the X-rays on the plastic sheet 4, the sheet 4 is rolledover the rollers and moved past a detector device 6. The detector device6 is not subjected to X-ray radiation and can therefore not be damagedby it. The sheet and rollers may comprise a precise guidance, e.g. a pinfeed system and have synchronization markings. In the present example,the sheet is an endless belt.

[0042] The detector device has a longitudinal extension parallel to therollers (not visible in the drawing) and must therefore not be movedover the plastic sheet since the sheet itself moves over the detectordevice along its entire width. The detector device may be connected to acomputer via appropriate leads, for evaluation of the scanned voltagedifferences.

[0043] Depending on the intensity of the radiation and on the propertiesof the plastic sheet, a charge difference may occur not only on the sideof the plastic sheet facing the X-ray source 1 but also in the area ofthe plastic sheet 4 facing away from the X-ray source. For evaluation,both regions of the plastic sheet can be used.

[0044]FIG. 2 shows an embodiment of an X-ray converter 2 in accordancewith the invention. A partial section of the entire converter of FIG. 1is illustrated, including the lower roller 5. The plastic sheet 4 isillustrated with exaggerated thickness for reasons of clarity. Referringto the rear portion of the converter 2 at the right hand part of FIG. 2,the plastic sheet 4 is seen to be lined on one side thereof with anarray of mutually separated electrically conducting pads 10. The pads 10are electrically insulated from each other via the plastic sheet 4. Acharger 12 is disposed proximate the converter 2 and contacts the pads10 to apply electrical charge thereto. The charger 12 is connected to anappropriate power supply 14. As can be seen on the left portion of FIG.2, the side of the plastic sheet 4 opposite to the pads 10 is coveredwith a uniform electrically conducting sheet 16. The sheet 16 can bemaintained at ground potential through contact with an electricallygrounded and conducting surface 18 of the lower roller 5. A detectordevice 6 is located at the lower rear portion of the converter 2 andcomprises a linear array of detection units 20. The detection unitscommunicate with an analysis unit 22 via suitable cable connection 24.The embodiment of FIG. 2 operates as follows. In an initial step therollers 5 of FIG. 1 ( only the lower one of which is illustrated in FIG.2 ) are set into rotation by a suitable drive motor in the directionindicated by arrow 26. The pads 10 located at the rear of the converter2 thereby pass by charger 12 and are charged thereby to a suitablevoltage which is typically in the range of 50 to 100 volts. As the lowerroller 5 continues to rotate, the plastic sheet with its associatedcharged pads 10 travels over the top roller 5 see FIG. 1 ) and proceedsin a downward direction at the front, left portion of the converter 2.At this point in time, rotation of the lower roller 5 is interrupted andthe converter is exposed to X-ray radiation 28. The X-ray radiationpasses through the thin layer of pads 10 and penetrates into the plasticsheet 4 to ionize materials in the plastic sheet 4. As a result of theseionization processes, a voltage decrease between a given pad 10 and theoppositely disposed conducting sheet 16 which is proportional to theX-ray dose absorbed by that portion of the sheet 4 proximate a given pad10 and therefore to the X-ray intensity incident on that pad 10.Following exposure, the X-ray source 1 (see FIG. 1) is switched off andthe rollers 5 are once more set into rotation in the direction of arrow26. Exposed pads 10 are thereby caused to pass by detector array 6 whichdetects the residual voltage in the respective pad 10 by means ofdetection units 20 and passes this information on to analysis unit 22for image construction.

[0045] All the features shown in the description, the following claimsand the drawing may be essential to the invention either individually orcollectively in any arbitrary combination.

List of Reference Numerals

[0046] 1 X-ray source

[0047] 2 X-ray image converter

[0048] 3 person

[0049] 4 plastic sheet

[0050] 5 roller

[0051] 6 detector device

[0052] 10 pads

[0053] 12 charger

[0054] 14 charger power supply

[0055] 16 conducting sheet

[0056] 18 roller ground surface

[0057] 20 detection units

[0058] 22 analysis unit

[0059] 24 cables

[0060] 26 rotation direction

[0061] 28 impinging X-rays

I claim:
 1. An X-ray image converter for recording and evaluatinginformation which can be detected within suitable radiation regions, e.gX-ray examination of persons (3), animals or objects or for scientificand technical purposes such as e.g. analysis or controls, comprising acarrier (4) on which the X-ray radiation impinges and effectscharacteristic changes, characterized in that the carrier (4) is asheet, in particular a plastic sheet and that for detecting thecharacteristic change, a detector device is provided which scans thesurface of the sheet during relative motion with respect to the sheet orwhich detects the information in a different fashion.
 2. The X-ray imageconverter according to claim 1, characterized in that the sheet hasuseful properties to detect the changes such as e.g. electricallyconducting surfaces (electrodes) on one or both surfaces or also inbetween, which are electrostatically charged before exposition and whichare scanned after exposition to measure the charge or voltagedifferences caused by irradiation or in that a magnetic effect isutilized for detection or that physical methods are combined.
 3. TheX-ray image converter according to claim 1, characterized in thatrollers (5) or cylinders are provided for retaining and moving the sheet(4) in a direction relative to the detector device (6) by means of whichthe sheet is moved over the detector device after exposition.
 4. TheX-ray image converter of claim 3, characterized in that the detectordevice, and/or a charger, is integrated in one or both of theabove-mentioned rollers.
 5. The X-ray image converter of claim 1,characterized in that the detector device (6) can be moved over thecarrier (4) in one or two directions in dependence on the number andarrangement of the measuring points of the detector device.
 6. The X-rayimage converter of claim 1, characterized in that more than one sheetplane, disposed one behind another with respect to the path of the rays,are exposed simultaneously and subsequently scanned and evaluated toreceive more information and calculate improved image results, whereinboth sheet regions between the rollers and both rollers can besimultaneously utilized, if rollers are provided for retaining andmoving the sheet.
 7. The X-ray image converter of claim 2, characterizedin that one side of the sheet is provided with an electricallyconducting coating.
 8. The X-ray image converter of claim 2,characterized in that one side of the sheet is provided with manyelectrically conducting insulating surfaces which form pixels, i.e.individual image points, wherein should a conducting surface already beused, the other opposing side of the sheet is used for the pixels. 9.The X-ray image converter of claim 2, characterized in that the twosurfaces of the sheet or the electrodes or pixels are charged with anelectric voltage before irradiation, that the charge or voltagedifference is reduced through irradiation and that after irradiation,the electric voltage or voltage difference between the two sheet sidesis measured (scanned) at the individual image points and evaluated. 10.The X-ray image converter of claim 2, characterized in that the detectordevice (6) comprises a field effect transistor or an operationamplifier, having an FET input, as detector for scanning the pixel side.11. The X-ray image converter of claim 1, characterized in that, forrecording spatially resolved information, several carriers are disposedat different spatial positions relative to the object to be recorded.12. The X-ray image converter of claim 1, characterized in that forrecording spatially resolved information, several radiation sources aredisposed simultaneously or sequentially at different spatial positionsrelative to the object to be recorded, wherein X-ray tubes having 2 ormore effective anode regions (focal spots), mechanical movement of thetube or use of scattering means may be provided.
 13. The X-ray imageconverter of claim 1, characterized in that the information recorded bythe detector device is evaluated and displayed by means of a computer.14. The X-ray image converter of claim 13, characterized in that theinformation recorded by the computer is locally stored, transported viadata communication, printed onto transparent film or paper or othermedia or protected from unauthorized access, changes or abuse, eitherintentionally or unintentionally through cryptological methods and/orelectronic authority checks.
 15. The X-ray image converter of claim 13,characterized in that the information processed into images is shown incolor to increase the meaningfulness, facilitate interpretation, displayadditional information or for other reasons.
 16. The X-ray imageconverter of claim 1, characterized in that secondary radiation, strayradiation, “fluorescence responses”, diffraction, grid diffractioneffects, certain spectral ranges selected from the object, afterglow orpolarization effects are recorded from the examined objects, areevaluated and represented as an image or in a different fashion orintegrated in other images or evaluations, as well as actual sourceslocated in the object itself.
 17. The X-ray image converter of claim 1,characterized in that a shadow casting attachment may be mounted infront of the inventive X-ray image converter to calculate, through imageprocessing, the direction of the impinging irradiation from the recordedimages by means of the shadows cast by the attachment to obtain, afternumerical calculation in the computer, i.a. a similar imagerepresentation as through a lens focussing the rays in front of theimage converter and that additionally or instead of the attachment,other shadows from the field of view, in particular also shadows of theobject are taken into consideration, wherein additional spatialinformation and information concerning physical response of the objectto the radiation is very useful and essential for certain evaluations.18. The X-ray image converter of claim 1, characterized in thatdifferent spectral regions of the source or sources, e.g. the X-raytube, are applied for the same examination, either simultaneously orimmediately following one another to permit or improve detection of theproperties of the examined object, e.g. a tumor or a defective locationby combining the different information in most cases by a computer. 19.The X-ray image converter of claim 2, characterized in that the detectordevice for scanning the image utilizes substantially the sameelectronics as a flat bed scanner for paper (e.g. format A4 or USletter) or a fax machine when scanning the inserted documents, thedifference being that the first step of the input elements reacts not tolight (light to dark) but to voltages or charges or to another physicaleffect such as e.g. magnetic fields or electromagnetic fields.
 20. TheX-ray image converter of claim 1, characterized in that the carrier orthe sheet may consist of several layers and that also more than onecarrier may be used in cooperation with specialized functions, whereinthe movements may be partly identical and partly different and thatcarriers may also contain other passive and active elements toeffectively support the technical functions before, during and afterirradiation.
 21. The X-ray image converter of claim 2, characterized inthat an electret is used as carrier or part or layer thereof whichindependently creates D.C. voltage (polarization voltage).
 22. The X-rayimage converter of claim 1, characterized in that the claims can beeffectively combined to carry out basically novel or improvedexaminations and permit or facilitate detection and illustration ofdetails.
 23. Method for recording X-ray images in X-ray examinations ofpersons, animals or objects, characterized by the following methodssteps, that the object to be examined is irradiated with X-rayradiation, that the X-ray radiation emitted by the object or transmittedthrough the object is received by a carrier (4), and that the change ofthe charge carrier on the surface of the carrier (4) is detected forevaluation purposes.